Snowshoes have long been used for walking on snow or ice covered terrain. A conventional snowshoe has a frame covered by a membrane, a front claw on the bottom front of the membrane, and straps to attach the snowshoe to a user's foot. The front claw is usually pivotally attached to the frame, beneath the ball of the user's foot. The user's weight at the ball of the foot causes the front claw to dig into the underlying terrain, providing friction that enables forward motion.
When used on level or uphill terrain, the snowshoe allows the user to walk about on snow or ice. Although the back of the snowshoe tends to drag along and skate or slide, the front claw permits forward motion because the user's center of gravity remains in a stable position.
It is known in the art to provide a flap-like cleat on the bottom of a snowshoe to improve its hill climbing ability. The cleat front hinges to the snowshoe, and the cleat "closes" against the snowshoe when pressed against the snow or ice. When the snowshoe is lifted, a spring urges the back of the cleat away from the snowshoe, into an "open" position preventing the snowshoe from sliding backward, thus promoting uphill use. However snow and ice debris can accumulate within the cleat, hampering snowshoe performance by preventing the cleat from fully closing.
Although suitable for level and uphill terrain use, conventional snowshoes do not perform well downhill because the rear of the snowshoe tends to skate or slide on the terrain surface. This skating prevents the user from maintaining a stable body position over the snowshoe. Commonly the user's weight is too far forward, causing the front claw to act as a fulcrum point about which the user pivots forward, usually just before falling to the ground. On the other hand, if the user's weight is shifted rearward, the snowshoe skating usually results in a backward fall backward because a stable body position cannot readily be maintained.
Conventional snowshoes suffer from other deficiencies as well. Often the front claw accumulates snow and ice, diminishing the claw's ability to bite into the terrain and to create friction. In some designs, the snowshoe is allowed to pivot freely on the front claw mounting axis, with the result that the rear of the snowshoe drags with each step. This dragging retards rapid user movement, such as running. Other designs minimize the rear dragging by mounting the front claw so as to urge the snowshoe to return to a horizontal disposition with each step, a configuration that promotes running. But as it is lifted from the terrain with each step, the snowshoe pivots downward about the front claw's mounting axis as the snowshoe tries to return to a generally horizontal disposition. As a result, the snowshoe front pivots downward and tends to accumulate snow and trip the user, while the snowshoe rear pivots upward and throws any snow thereon forward, usually striking the user's legs.
Because of the above limitations, conventional snowshoe travel tends to be slow, and considerable practice is required before any proficiency is attained. Although snowshoe travel could provide meaningful exercise, the inability to run, and to travel downhill confidently limits recreational snowshoe use.
In conclusion, there is a need for a mechanism to minimize skating at the back of a snowshoe, and to permit a snowshoe to be used on downhill terrain. Such a mechanism should not add appreciable weight or cost to a snowshoe, and preferably could be retrofitted. Also needed is a mechanism to minimize snow accumulation at the front claw of a snowshoe. Finally, there is a need for a mechanism that minimizes snow tossing without dragging the snowshoe rear, and that lifts the snowshoe front over obstacles so as not to trip the user. A snowshoe equipped with these mechanisms would permit running and other beneficial snowshoe exercise, even by a novice. The present invention meets these needs.